Rheostat



May 8, w23. l ,l-54,030

F5. AUSTRHAN RHEOSTAT Filed July 14 1922 mumtoz Ralph Brooke usn'on.

@ @mf/wwf @wf Patented May 8, 1923.

UNITED *i sTATEs PATENT OFFICE.

lRALPH BROOKE AUSTRIAN, l' NEW YORK, N. Y., ASSIGNOR TO UNION RADIO CORPO- RATION, OF NEW`YORX, N. Y., A CORPORATION 0F NEW YORK.

RHEOBTAT.

Application led July 14, 1922. Serial No. 574,898.

To all lwlwm z't may concern:

Be it known that I, RALPH BROOKE Ans- TRIAN, a citizen of the United States, and a resident of the city, county, and State of New York, have invented an Improvement in Rheostats, of which the following is a specification. t My invention relates to a rheostat which is suitable for a variety of purposes but finds its greatest utility in handling small currents in connection with instruments such, for instance, as in the case of radio telegraphic apparatus.

Some of the objects of my invention are 1u to produce a simple and economical construction which can be easily and cheaply assembled and will have the minimum number of parts. l

My invention also aims to roduce a rheostat in which a relatively arge radiating surface is provided and in which a convenient and positive means of making contact is incorporated.

Referring to the drawin which illustrate the preferred form o my invention, although it willbe understood t at I do not intend to confine myself thereto, it being obvious that many" changes may be made without departing ",from the spirit of my invention,

I have shown: In Fi re 1, a bottom view of my iinproved r eostat;

In Figure 2, a top view thereof;

In Figure 3, a side view;

In Figure 4, a sectional view taken on the lines 4, 4 of Fig. 1.

It will be seen from the drawings that the construction illustrated therein clomprises a base member of insulating material 1, upon which the other parts are supported. The resistance wire 2 is wound about a {lexible strip of fibre or other insulating material 3, preferably inthe lat form' illustrated in the drawings, so as to expose'substantially all of the wire to radiation. Strip 3 is supported at its ends by means of a supporting member, which may be conveniently made of one piece of metal bent into L-shape, having a vertical leg 4 and a horizontal leg 5. Leg 4 is perforated to take the bolt and nut 6, which passes through the fibre member 3 and thus supports one end of it in position. The upstanding leg 4 is provided with a projection 7 which acts as a limiting stop for the movement of the contact member, as will be hereafter explained. The horizontal leg 5 is perforated to take'the binding post 8, which passes through the base 1, and which may be provided with a soldering lug 9 to take the wires to be connected to the rheostat. The binding post thus not only serves its ordinary function of connecting the wires to the apparatus, but also constitutes the sole means of holding the supporting member 4 in position. The contact member 9, movable in an arc about the central pivot of the rheostat is fastened to a bushing 10, held upon the shaft 11 by a set screw 12, or in any other suitable manner, the shaft 11 being prevented from axial movement by means of the collar 13, and being fastened at its opposite end to an operating knob or handle 14. Operating handle 14 may, if desired, carry an indicating pointer 15. Contact is made to the contact member 9 by means of a spring Contact 16, which is held in position at its outer end by means of one of the binding posts 8. Carried by the base, and preferably integral therewith is an insulating ridge 17 formed into an arc of the saine curvature of the arc of movement of the Contact member 9. Ridge 17 engages the strip 3 and resistance wire 2 adjacent its lower edge and positions the strip so that its upper edge is presented to the contact member 9 throughout its movement. rlhe arrangement is such that a very small contact only is made between the ridge 17 and the resistance wire, and the radiation is thus not materially alfected.

It will be noted that upstanding projections 7 on the supporting members 4 are located at opposite edges of the supporting members and that such supporting members are less in height than the insulating strip 3. By this arrangement I am enabled to use the upstanding projections 7 as limiting stops in one case (for instance as shown in Fig. 4) the arrangementbeing such that the contact member 9 will bein contact with the resistance wire 2 when it reaches the limit ing sto 7, and in the other case the position of the imiting stop being such that the contact member 9 is in contact with the insulating strip 3 only when it reaches the limiting stolp.

t will also be seen that the resistance wire is easily and firml fastened to the insulating strip 3 by ing threaded through a hole in strip 3 at one end, and at the opposite end by means of the screw and bolt 6, thus affording electrical contact with the support and binding post.

Suitable means, such as the bolts 18 are provided for fastening the rheostat to a panel or support, the means shown are illustrated merely by Way of example, since they form no part of my invention and may be changed to suit the particular circumstances of the use to Which the rheostat is applied.

What I claim is:

1. In a device of the kind described, a flexible insulating strip, a resistance Wire wound thereon, means for supporting the strip adjacent its ends and a base having a positioning ridge adapted to cooperate with the strip.

2. In a device of the kind described a fiat strip of insulating material, a wire resistance element wound thereon, a base of insulating material, means carried thereby for supporting the strip adjacent its ends With one edge adjacent the base, said base being provided with an arcuate ridge 0f insulating material adapted to cooperate with the strlp to position it.

3. In a device of the kind described a flat strip of insulating material, a wire resistance element Wound thereon, a Contact adapted to cooperate therewith and movable over an arcuate path, a base of insulating material, means mounted thereon for supportingthe strip adjacent its ends and a positioning ridge on the base adapted to cooperate with the strip to hold it in the arc of movement of the contact.

4. In a device of the kind described a strip of insulating material, a wire resistance element Wound thereon, a base of insulating material and a support adapted to support one endfof the strip com using a single piece of metal bent into L orm and having a projection extendin beyond the insulating strlp to act as a imiting stop.

5. In a device of the kind described a strip of insulating material, a wire resistance element Wound thereon, a base of insulating material, a support comprising an L shaped piece of metal adapted to support one end of the strip anda binding post passing through the base and the support and constituting the sole means of holding the latter in position on the base.

6. Ina device of the kind described a strip of insulating material, a wire resistance element Wound thereon, a base of insulating material, a su port comprising an L shaped piece of metal) having an'upstanding leg to'which the strip is adapted to be attached and a projection thereon adapted to act as a limiting stop and a perforate horizontal leg adapted to be held in contact With the base, a movable contact member, a spring member adapted to supply current to the contact member and a Ibinding post adapted to hold the support and spring member in position.

In testimony whereof, I have signed my name to this-specification this 13th day of July, 1922.

RALPH BROOKE AUSTRIAN. 

